1. Field of the Invention
The present invention is in the field of solar panels, and more specifically relates to a structure that provides an electrical terminal for a solar panel.
2. The Prior Art
The conventional technique for electrically terminating a photovoltaic solar panel is to attach a wire ribbon made of tin-plated copper to a conductive film on the photovoltaic substrate surface. The attachments are made by a soldering technique. The problems that can occur with soldered joints are well known, and are aggravated by the exposure of the solar panels to outdoor conditions. U.S. Pat. No. 5,268,038 of Riermeier, et al. issued Dec. 7, 1993 shows a terminal in which a conductive ribbon is soldered to conductive strips within the panel. Also, FIG. 1, below, shows a typical prior art termination system.
Dissatisfaction with soldered connections was evident as early as Jul. 24, 1973 when U.S. Pat. No. 3,747,327 issued to Uchiyama. He showed that a compressed elastomeric member can exert a continuing force on conductive elements, thereby maintaining a solderless contact.
In U.S. Pat. No. 4,776,896 issued Oct. 11, 1988 to Umemoto, there is shown the use of a leaf spring to maintain contact between elements of a solar battery.
The desire for solderless contacts became a necessity with the advent of removable electric circuit cards. In U.S. Pat. No. 4,993,957 issued Feb. 19, 1991 to Shino, there is shown a contact employing a body of silicone rubber containing a silver powder that is urged against a conductor to provide a contact.
In U.S. Pat. No. 5,281,148 issued Jul. 25, 1994, Thompson shows a connector for electric circuit cards that uses a biased ball bearing contact.
Finally, in U.S. Pat. No. 2,224,343 issued Dec. 10, 1940, Grimaldi shows a swivel connection that employs springs and a conductive ball to eliminate twisting and kinking in appliance cords.
Thus, although the problem of designing a reliable solderless electrical terminal for a solar panel has been recognized, it remained for the present inventor to delineate a specific successful solution to the problem, particularly as it relates to the termination of solar panels.